This state machine diagram example shows a state diagram for the history of a ticket to a performance.
- The initial state of a ticket (shown by the black dot) is the Available state. Before the season starts, seats for season subscribers are assigned.
- Individual tickets purchased interactively are ﬁrst locked while the customer makes a selection.
- After that, they are either sold or unlocked if they are not chosen.
- If the customer takes too long to make a selection, the transaction times out and the seat is released.
- Seats sold to season subscribers may be exchanged for other performances, in which case they become available again.